swimming


	SWIMMING

MICHAEL PHELPS WINNING GOLD AT THE BEIJING OLYMPICS

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SWIMMING

IS GOOD VISION NECESSARY FOR SWIMMING?

Swimming is one of the country's most popular activities being enjoyed by over 10 million people. You would think that excellence in swimming cannot be achieved without good vision. However, Olympic and Commonwealth gold medallist, Ian Thorpe of Australia (known as Thorpedo) admitted not having good distance vision as he was unable to see his time on the scoreboard when he broke a world record at the Commonwealth Games.

For the rest of us clear vision is essential when swimming so as to be able to see

to the end of the lane
to keep to your lane
others in the race
to avoid bumping into others
your coach, child or teacher

DIVING

SCUBA diving involves the use of oxygen and an inert gas at depths no more than 60 metres. Decompression sickness can cause bubbles in the tear film and rarely inside the eyeball itself. If the pressure behind the face mask is not equalised it can cause swelling of the eyelids and bursting of the blood vessels of the white of the eye. Long term effects of diving include loss of side vision, defective colour vision and loss of retinal pigment.

VISION CORRECTION FOR SWIMMING

For many, prescription swimming goggles will be the safest form of vision correction. Many Olympic swimmers wear goggles even though they do not need any eyesight correction. A selection of the current models is shown to the left.

SWIMMING WITH
CONTACT LENSES

Contact lenses are a popular form of vision correction for swimmers. There is no problem with steaming up and tightly fitting goggles can be uncomfortable if worn for an extended period of time. However, contact lenses are not without their drawbacks and are now not generally recommended for swimming due to problems with chlorine, contaminants such as acanthamoeba ( a small one-celled protozoa) or bacteria which can cause a serious eye infection in soft lenses and possible loss of a contact lens in a swimming pool with rigid lenses. If contact lenses are to be worn, the use of tight fitting swimming goggles is recommended and a thorough cleansing and disinfection of the contact lenses after use can lower the risk of infection.

In salt or sea (hypertonic) water and chlorinated swimming pool water, soft lenses tend to stick to the cornea (front of the eye) due to an osmotic effect tightening the lens. Ideally one should wash the eyes with sterile water or saline and wait for twenty minutes after leaving the swimming pool before taking out the contact lenses. There is also a risk of infection from acanthamoeba or toxic reactions from chemicals in the water.

In fresh (hypotonic) water, soft lenses tend to enlarge and float about in the eye so care must be taken to avoid loss.